Add ObjectType filtering support for the Locate operation

This change updates Locate operation support in the PyKMIP server,
allowing users to filter objects based on the object's Object Type.
Unit tests and integration tests have been added to test and verify
the correctness of this feature.

Additionally, the Locate demo scripts have also been updated to
support Object Type filtering. Simply use the "--object-type" flag
to specify an Object Type enumeration for the Locate script to
filter on.

kmip/demos/pie/locate.py

@@ -35,6 +35,7 @@ if __name__ == '__main__':
     name = opts.name
     initial_dates = opts.initial_dates
     state = opts.state
+    object_type = opts.object_type
 
     attribute_factory = AttributeFactory()
 
@@ -84,6 +85,20 @@ if __name__ == '__main__':
         else:
             logger.error("Invalid state provided: {}".format(opts.state))
             sys.exit(-3)
+    if object_type:
+        object_type = getattr(enums.ObjectType, object_type, None)
+        if object_type:
+            attributes.append(
+                attribute_factory.create_attribute(
+                    enums.AttributeType.OBJECT_TYPE,
+                    object_type
+                )
+            )
+        else:
+            logger.error(
+                "Invalid object type provided: {}".format(opts.object_type)
+            )
+            sys.exit(-4)
 
     # Build the client and connect to the server
     with client.ProxyKmipClient(